The present invention relates to an agent for reducing the levels of odorous gases such as ammonia, mercaptans, amines and aldehydes. More specifically, the present invention relates to a novel deodorizer in white particulate form that contains as main ingredients zinc oxide and at least one oxide (hereinunder referred to as oxide A) selected from the group consisting of aluminium oxide, silicon dioxide and mixtures thereof and which has very good adsorption characteristics.
Hydrogen sulfide, ammonia, mercaptans, amines, aldehydes and other odorous gases that are generated in daily life have caused an increasing amount of social concern about the deleterious effects they have on the biosphere and environment. In response to these concerns, a variety of deodorizers that are capable of reducing the target odorous gases have been proposed and put to practical use. Deodorizers for use in daily life have to satisfy the following minimal requirements:
(1) they must be capable of efficient reduction of the levels of hydrogen sulfide, ammonia, mercaptans, amines, aldehydes and other odorous gases that are generated in daily life; PA1 (2) they must be safe to use; PA1 (3) they must be easy to handle; PA1 (4) they must be inexpensive; and PA1 (5) they must offer a feeling of cleanliness.
However, none of the conventional deodorizers satisfy all of these requirements, nor do the most recently developed products. Activated carbon which is the most popular deodorizer in use today is highly effective in reducing mercaptans and amines but is not equally effective against hydrogen sulfide and ammonia which are typical of the odorous gases that are generated in daily life. In an attempt to solve this problem, a product has been developed that has an acid, an alkali or a certain halide supported on activated carbon. However, because of the use of an acid or alkali, this product requires very careful handling to avoid any danger to humans and hence is not suitable for daily use. Furthermore, the inherent black color of activated carbon limits the scope of use of deodorizers based on activated carbon.
Iron sulfate (FeSO.sub.4) having L-ascorbic acid bound thereto is effective against basic odorous gases such as ammonia and amines but is little effective in reducing hydrogen sulfide, mercaptans and aldehydes. Furthermore, this product dissolves in water and hence is not suitable for the purpose of deodorizing wet gases.
Deodorizers classified as chemical odor modifiers are also available but many of them have strong acidity or alkalinity and the kinds of odorous gases that can be effectively controlled by these odor modifiers are limited. In addition, such deodorizers are sensitive to moisture and/or a dry atmosphere.
Organic deodorizers have low heat resistance, are difficult to process, and are expensive.